Structure for and method of transfer, exchange, control regulation, and storage of heat and cold



June 20, 1950 HAZARD 2,512,545

STRUCTURE FOR AND METHOD OF TRANSFER, EXCHANGE, CONTROL REGULATION, AND STORAGE OF HEAT AND COLD Filed June 11, 1948 10 Sheets-Sheet 1 IN VEN TOR.

[Peder/ck E. r /azard Jam June 20, 1950 F. E. HAZARD 2,512,545

STRUCTURE FOR AND METHOD OF TRANSFER, EXCHANGE, CONTROL REGULATION, AND STORAGE OF HEAT AND COLD Filed June 11, 1948 10 Sheets-Sheet 2 f 3/ a7 i F/ 1/ INVENTOR; fiedr/ck .5. Hazard June 20, 1950 F. E. HAZARD 2,512,545

STRUCTURE FOR AND METHOD OF TRANSFER, EXCHANGE, CONTROL REGULATION, AND STORAGE OF HEAT AND cow vINVENTOR.

Fear/2k f. A azam/ BY MM June 20, 1950 F. E. HAZARD 2,512,545

STRUCTURE FOR AND METHOD OF TRANSFER, EXCHANGE, CONTROL REGULATION, AND STORAGE OF HEAT AND cow Filed June 11, 1948 10 Sheets-Sheet 4 I ll 0 :1 f H I ll 4 /5' ,/1

IN VEN TOR.

lgederz'o f. Hazard MW AGENT 2,512,545 CONTROL HAZARD STRUCTURE FOR AND METHOD OF TRANSFER, EXCHANGE,

REGULATION, AND STORAGE OF HEAT AND COLD Filed June 11, 1948 10 Sheets-Sheet 5 l LiZZIIIIZ-K IN V EN TOR. flea slick E. zqczzard.

June 20, 1950 F. E. HAZARD 2,512,545

STRUCTURE FOR AND METHOD OF TRANSFER, EXCHANGE, CONTROL REGULATION, AND STORAGE OF HEAT AND COLD Filed June 11, 1948 10 Sheets-Sheet 6 503 Fig,

INVENTOR. Freder/ck 15 Hazard F. E. HAZARD June 20, 1950 2,512,545 STRUCTURE FOR AND METHOD OF TRANSFER, EXCHANGE, CONTROL REGULATION, AND STORAGE OF HEAT AND COLD Filed June 11, 1948 10 Sheets-Sheet '7 was 5 INVENTOR. 5 flazard Freder/ck lam/ June 20, 1950 F E HAZARD 2,512,545

STRUCTURE FOR AND METEoU'oE TRANSFER, EXCHANGE, CONTROL REGULATION, AND STORAGE OF HEAT AND cow Filed June 11, 1948 10 Sheets-Sheet 8 l ]N 1 5 N T 02 Freda/ck Z/czza/d June 20, 1950 F. E. HAZARD 2,512,545

STRUCTURE FOR AND METHOD OF TRANSFER, EXCHANGE, CONTROL REGULATION, AND STORAGE OF HEAT AND COLD Filed June ll, 1948 10 Sheets-Sheet 9 M q AJMW .r/imf 2,512,545 CONTROL June 20, 1950 F. E. HAZARD STRUCTURE FOR AND METHOD OF TRANSFER, EXCHANGE REGULATION, AND STORAGE OF HEAT AND COLD Filed June 11, 1948 w m t N e f e V w .r h S mwQ \NQ H 0 m j N? mmmi R RE NQT N3 3% Q? 3 0 \Rl N v QQ W Q3 1% Patented June 20, 1950 UNITED STATES PATENT OFFICE STRUCTURE FOR AND METHOD OF TRAN S- FER, EXCHANGE, CONTROL REGULATION, AND STORAGE OF HEAT AND COLD 22 Claims.

This invention pertains to apparatus and methods for the transfer, exchange, control, regulation and storage of cold and heat in refrigerating apparatus, heating apparatus, and combined refrigerating and heating apparatus.

This application is a continuation-in-part of my co-pending application for patent Serial No. 579,185, entitled Refrigerating Apparatus, filed February 22, 1945, and incorporates the full subject matter of the application mentioned as well as certain improvements in fundamental structure and methods of use thereof discovered by me during the pendency of such application.

One object of the invention is to provide a heat transfer and exchange system which will enable the temperatures of ultimate heat absorbing or dissipating apparatus to be maintained and controlled within limited ranges irrespective of the temperature at which other portions of the system are maintained.

Another object of the invention is the provision of structure and methods whereby desired thermal conditions may be developed in the several volumes of heat transfer and exchange fluid contained in a plurality of reservoirs arranged in heat transfer and exchange relation to one another, at least one of the reservoirs being a master reservoir and having as its chief purpose that of storing in the fluid therein a reserve of heat or cold, and all the other reservoirs being subsidiary in some degree to the master reservoir and each to some degree functioning for storage of heat or cold, and certain of the other reservoirs being subsidiary one to another so that there can exist between the fluids in immediately interrelated reservoirs a temperature difierential arranged in readily controllable stages or steps.

Another object of the invention is the provision of means and methods whereby the heat units absorbed by a primary thermal conditioning means in providing refrigeration may be removed from such means and put to productive use to provide heat, or the primary thermal conditioning means, in producing heat, can be applied to create a condition of cold for purposes of refrigeration.

Still another object is to provide a refrigerating or heating system having a large thermal reserve or storage capacity for heat or cold forming a thermal flywheel which may be called upon for heat absorption or dissipation, thereby assuring a uniform level of performance in ultimate heat transfer and exchange units, during the periods of demands on the system for heat and/or ate production ability of the source of heat or refrigeration.

Another object is to provide structure for heatintegrated with the structure anteceding it in the system thereby making possible the use, particularly as ultimate heat transfer and exchange units, of movable members which may be swung or otherwise moved w thout disturbing their ability to be directly refrigerated or heated by the fixed portion of the system.

Yet another object is to provide structure for refrigeration or heating, utilizing as a source of heat and/or cold the condensers and evaporators, respectively, of one or more complete compressorcondenser-evaporator units functioning as a heat pump or heat pumps, the stored or reserve heat absorption or heat dissipation capacity of the structure, mentioned hereinbefore, eliminating the necessity for frequent wear-inducing and excessive power-consuming cycling of the compressor-conde'nser-evaporator unit, the reserve or storage capacity also readily permitting the motor operation to be largely limited to those periods wherein off-peak low cost electric rates are in effect.

Yet another object is to provide, for use in conjunction with the main heating or refrigeration system or combined refrigerating-heating system, a supplemental system of heat pickup or dissipation of a type exposed to conditions such as those extant in the ground, in water or in the air, whether in naturally occurring or produced condition, the supplemental system being such as to be capable of serving to balance an integrated heating-refrigerating system; or to pick up or dissipate heat units and thus relieve the primary source of heat or cold from operation, otherwise required; or which may serve as a primary source of heat or cold.

Another object is to provide means whereby heat units, once produced and present in a carrier such as air, water or the like may be picked refrigeration in excess of the relatively immediup and re-used, when the carrier for any reason is to be disposed of, for heating a new volume of the carrier or for other heat unit utilization.

Another object is the provision, in apparatus including a common means for producing both heat and cold such as, for instance, an integrated compressor-condenser-evaporator unit used as a heat pump, and in which apparatus both the heat and cold sides are productively utilized, of a means for balancing the heat and/or cold utilizing sides with one another, irrespective of demands on the system for heat or cold, which might, without such balancing means, throw the whole system into an ineflicient operating phase.

A still further object is to provide means whereby a primary source of heat and/or cold may be positioned remote from the location at which the heat or cold is to be utilized, a thermally conditioned fluid being circulated through appropriate conduits, the conduits being capable of being interconnected as desired .into heat transfer and exchange relation with subsidiary secondary reservoirs and ultimate heat transfer and exchange units served by such subsidiary secondary reservoirs, so that various temperatures may be produced in various portions of an installation at will, irrespective of where these portions may be located with respect to one another or with respect to other portions of the system.

Another object is to provide means and methods by which the temperature of a space or object to be cooled or heated is regulated by controlling the volume of heat transfer and exchange fluid brought into heat transfer and exchange relation with the space or object with which heat units are to be exchanged.

Another object of the invention is the provision of structure whereby the temperature of the fluid in an ultimate heat transfer and exchange unit may be changed from one range to another at will, thereby making it possible for a space to be heated to variant temperatures or for a, refrigerated space to be utilized at temperature ranges controllable, for instance, from those sufliciently low to maintain frozen foods to those sufliciently high to prevent food dehydration or freezing.

Another object of the invention is to provide structure whereby the temperature of an ultimate heat transfer and exchange unit, one or more stages removed from a master secondary reservoir, may be normally controlled for the major portion of its use period within a predetermined temperature range and wherein means are provided for temporarily substantially increasing the heat transfer and exchange ability of the utlimate heat transfer and exchange unit at will for limited periods by flowing heat transfer and exchange fluid through such unit at a temperature considerably differing from that at which the heat transfer and exchange fluid is normally flowed therethrough.

Still another object of the invention, particularly in its refrigeration-use phase, is the provision of structure wherein a coil type heat exchanger may be positioned within a fluid-flooded heat transfer and exchange unit, the heat exchanger being supported in the named unit in heat-insulated relation to the walls of the unit so that the heat transfer and exchange fluid forms the sole heat-unit conductive element.

Another object is the provision of refrigeration apparatus in which the temperature of the refrigerating medium is maintained at a relatively constant temperature as contrasted to the 4 variant temperature ranges characteristic of the refrigerating medium in a conventional direct expansion system.

An additional object is to provide apparatus for and methods of refrigeration in which a relatively high temperature refrigerant is placed in direct heat transfer and exchange relation to the space or object to be refrigerated, the surface of the heat transfer and exchange unit serving the space or object and/or the refrigerant itself being maintained at a temperature above the freezing point of water, thus reducing dehydration of foodstuffs to a negligible minimum, reducing moisture condensation and the freezing of moisture on the heat transfer and exchange unit or parts adjacent thereto, also eliminating the freezing of objects to the walls or shelves, making defrosting unnecessary, and achieving 'these results while maintaining the heat extraction ability of a low temperature refrigerant.

Other and further objects and advantages of the device and methods of the invention will become apparent from the detailed description which follows and from the drawings in which:

Fig. l is a diagrammatic showing, principally in section, of structure used in the invention wherein the high side of a primary thermal conditioning means comprising a complete compressor-condenser unit consisting of motor, compressor, condenser, receiver and expansion valve (the latter two not shown) is the principal source of cold and an exposed heat unit dissipating tank is an auxiliary source of cold, the structure also including a primary tank filled with heat transfer and exchange fluid in which the low side or evporator portion of the primary thermal conditioning means is immersed, and this showing also including portions of a secondary system comprising a master secondary reservoir, and certain subsidiary secondary reservoirs, which are shown typically interconnected in accordance with certain of the methods herein disclosed:

Fig. 2 is a diagrammatic showing, chiefly in section, of further subdivisions forming branch systems for the subsidiary secondary system and comprising individual ultimate heat transfer and exchange units associated with or comprising refrigerating compartments;

Fig. 3 is a diagrammatic showing following closely that of Fig. l but differing therefrom in indicating the installation of the high side or complete compressor-condenser unit remote from the secondary system;

Fig. 4 is a diagrammatic showing of structure permitting installation of the high side compressor-condenser unit, the low side evaporator, the primary tank and master secondary reservoir remote from the other portions of the system, pump means being provided for inducing the flow of the heat transfer and exchange fluid partly in lieu of the thermo-siphonic fluid flow generally characteristic of the showings of those figures preceding this one;

Fig. 5 is a diagrammatic showing of a modified and simplified form of the invention following the principles generally shown in Fig. l, the primary tank being eliminated;

Fig. 6 is a fragmentary showing of a modified form of structure whereby the primary unit low side or evaporator is in direct heat transfer and exchange relation with the fluid in the master secondary reservoir;

Fig. 7 is a diagrammatic showing of the structure of Fig. 1, modified in minor degree, wherein such structure is shown as being used for heating as well as for refrigeration;

Fig. 8 is a diagrammatic showing of a refrigeration-type system, utilizing the principles of the invention, wherein multiple reservoirs are shown arranged in series in sequentially succeeding subsidiary relation to one another;

Fig. 9 is a diagrammatic showing of the structure and methods of the invention wherein a plurality of reservoirs are arranged in series in a typical heating installation;

Figs. 10, 11 and 12 show modifications of the basic structure wherein means are provided for maintaining a relatively constant temperature for the majority portion of its use period in an ultimate heat transfer and exchange unitone stage removed from the master secondary reservoir and wherein during temporary periods the heat transfer and exchange capacity of the heat transfer and exchange unit may be substantially enhanced; and

Figs. l3, l4 and 15 show structure whereby an ultimate heat transfer and exchange unit two stages removed from the master secondary reservoir may, for temporary periods, be caused to have greater heat transfer and exchange capacity than generally characteristic of the usual operation of such ultimate heat transfer and exchange unit.

Broadly viewed, the structure comprises a generally closed system wherein a priry source of difierential from ambient temperature, ay be of any type, provides a desired thermal range in a volume of heat transfer and exchange fluid contained in a master secondary reservoir or tank. The mastsr-reservoir-contained fluid is flowed into heat transfer and exchange relation with the heat transfer and exchange fluid contained in other reservoir units comprising a subsidiary secondary system. The subsidiary secondary system is divided into branch subsidiary systems usually comprising reservoirs or heat exchangers containing heat transfer and exchange fluid, the branch system being connected in heat transfer and exchange relation with the portions of the system to which they are subsidiary; and these branch subsidiary systems may themselves be branched, if desired, into further similar subsidiaries, or they may be attached to or become the ultimate heat transfer and exchange units for cooling or heating spaces or objects. Each of the units comprising the subsidiary systems or branches functions independently, being related to the system or unit anteceding it only to the extent of reliance on the latter as its source of heat or cold.

The heat transfer and exchange fluid is of an uncompressed type, relatively unpressurized except as it may be solely by that condition it assumes within the thermal range at which it operates for heat transfer and exchange purposes, and should preferably have high thermo-siphonic flow characteristics.

To induce thermo-siphonic flow of heat transer and exchange fluid from each tank or reservoir to any or all tanks or reservoirs subsidiary thereto, the subsidiary reservoirs are preferably elevated or lowered, dependent on whether used for heating or refrigerating, with respect to the reservoir or tank to which each is subsidiary. Certain portions of each subsidiary system operate at a temperature differential from a preceding portion of the system, to induce thermosiphom'c flow between them. Certain of the conduit means which permit flow of heat transfer and exchange fluid from each reservoir to a reservoir subsidiary thereto have temperature control means associated with them permitting flow of heat transfer and exchange fluid therethrough only during those periods wherein the temperature of the heat transfer and exchange fluid in the more subsidiary reservoir is at an undesirable imbalance to the temperature of the heat transfer and exchange fluid in the reservoir antecedent thereto. If desired, pump means may be utilized to supplement the thermo-siphonic flow principle generally utilized throughout the systems of the invention.

Referring now to the drawings, in Fig. l is shown a conventional integrated compressorcondenser or high side unit Ill having a low side comprising an evaporator I3 operatively connected thereto, the integrated high and low side unit being hereinafter occasionally referred to as a primary thermal conditioning means. This apparatus is mounted on the insulated base shown, the evaporator thereof being positioned in heat transfer and exchange relation with a master secondary tank or reservoir I5. Reservoir I5 contains a suitable heat transfer and exchange fluid, and is preferably fully blanketed by insulation I5.

The primary thermal conditioning means is regulated to operate within a predetermined temperature range by a control means 9 which typically may be a pressure valve or a thermostat.

The insulated base is removably mounted to cover a primary tank I4 formed integral with master secondary reservoir I5, and tank I-I extends into reservoir I5 a distance, as shown. Tank I4, like reservoir I5, has a suitable heat transfer and exchange fluid therein and may be equipped with heat absorption fins I4 to accelerate heat exchange. The primary thermal conditioning means evaporator I3, shown in this instance as being of conventional coil type, is supported from the base shown, and is immersed in the heat transfer and exchange fluid in tank I I. A header or expansion space H5 is provided on reservoir I5 to permit the heat transfer and exchange fluid in such reservoir to expand or contract in accordance with its requirements.

Positioned at a point somewhat lower than the master secondary reservoir I5, is a subsidiary secondary reservoir I6, fully encompassed by insulation I6, this reservoir also having heat transfer and exchange fluid therein. A header II6, integral with the reservoir I6, is provided to accommodate expansion and contraction of the reservoir-held fluid. A heat exchanger I'I, typically in the form of a coil, is positioned in subsidiary secondary reservoir I6, this heat exchanger being in communication with reservoir I5 by means of a conduit I8, which extends from the bottom of reservoir I5, and another conduit I9, which extends to the top of such reservoir. Conduit I9 has in its length a temperature control means 20 typically comprising a thermostatic valve. It will be obvious that the heat transfer and exchange fluid in reservoir I5 may flow thermo-siphonically through heat exchanger II except to the extent that the flow of the fluid is cut off by temperature control means 20.

A conduit 2I in communication with subsidiary secondary reservoir It leads outwardly therefrom adjacent its bottom and another conduit 24 leads from a point adjacent the top thereof. By referring to Fig. 2, it will be seen that conduits 2|, 24, respectively, communicate with a heat exchanger 22, typically in the form of a coil, which is positioned within the walls of an ultimate heat transfer and exchange unit which latter typically may be of a refrigerator compartment 23. Compartment 23 is preferably encompassed by insulation 23', as shown.

Referring again to Fig. 1, it will be seen that another subsidiary secondary reservoir 26, en-

closed within insulation 26' and having an integral header I26, is positioned below master secondary reservoir [5. Subsidiary secondary reservoir 26 contains heat transfer and exchange fiuid and communicates with master secondary reservoir l by a conduit 21 and another conduit 28, there being a temperature control means 29, typically comprising a thermostatic valve, interposed in the line of conduit 28. Reservoir 26 is provided with conduits 30 and 32 and by again referring to Fig. 2, it will be seen that conduit 30 communicates with the bottom of a hollow walled portion of compartment 3| and conduit 32 communicates with the top of the hollow wall portion. Compartment 3! may be considered an ultimate heat transfer and exchange unit and typically may be another type of refrigerator compartment. The latter is shown as being encompased by insulation 3 l Referring again to Fig. 1, it will be seen that another subsidiary secondary reservoir 33, encompassed by insulation 33' and having an integral header I33, is positioned below master secondary reservoir i5. Reservoir 33, like reservoirs l6 and 26, contains heat transfer and exchange fluid and communicates with master secondary reservoir 1 5 by means of a conduit 34 leading from the bottom and another conduit 35 leading to the top of the last-mentioned reservoir. A temperature control means 36 is provided in the line of conduit 35. A conduit 31 leads from the bottom of reservoir 33 into communication with a hollow bottom portion 38 forming a base of a compartment 39, and another conduit 40 communicates between the top of the hollow bottom portion 38 and the top of the subsidiary secondary reservoir 33 as shown. Compartment 39 may be considered to be an ultimate heat transfer and exchange unit and may typically be still another type of refrigerator compartment. Compartment 3!! is preferably encompassed by suitable insulation 39'.

In the drawings referred to up to this point and in the foregoing description, tln'ee different types of refrigerator structure have been shown and described which constitute ultimate heat transfer and exchange units. These ultimate units are disclosed as being served from three individual subsidiary secondary reservoirs, the latter in this instance being shown as comprising two types. It will be obvious that there is no limit to the interrelated combinations of secondary reservoirs and ultimate heat transfer and exchange units that may be made. It is pointed out, however, that the subsidiary secondary reservoirs and ultimate heat transfer and exchange units, however formed or integrated, are each independently functioning, although interrelated heat transfer and exchange systems. The arrangement of the three subsidiary secondary reservoirs and the three refrigerated structures shown and described are merely examples of a few of the numerous ways in which the systems utilizing the methods of the invention may be interrelated.

Now referring to the upper right hand side of Fig. 1, it will be seen that there is provided an $581133? heat transfer and exchange system ineluding a tank 41 exposed to naturally occurring conditions and having on its exterior heat dissipating fins 4|. Tank 4| contains heat transfer and exchange fluid and in this instance is positioned above the master secondary tank l5. Extending from the bottom of the tank 4! is a heat transfer and exchange fluid conduit 42, the flow of fluid therethrough being controlled by temperature control means 43 typically in the form of a thermostatic valve. Conduit 42 extends into master secondary reservoir l5 and communicates with the latter adjacent its bottom. Another conduit 44 extends from the top of reservoir l5 to the top of the tank 4|, being in open communication with each. Tank M has an appropriate header, as shown.

Referring now to Fig. 3, there is therein shown a construction similar to that shown in Fig. 1, except that the complete primary thermal conditioning means high side unit is shown as it would appear when positioned at a lower level than the master secondary reservoir i5, as if such high side unit were located, for example, in a basement.

It will be obvious that, for refrigeration purposes, the complete subsidiary secondary systems should preferably be arranged below the master secondary reservoir, in order to most readily permit thermo-siphonic flow of the heat transfer and exchange fluid between each reservoir and the one to which it is subsidiary. The heat transfer and exchange fluid in colder condition will flow through the lowermost of the conduits interconnecting it in heat transfer and exchange relation with the reservoir subsidiary thereto, and, having served its heat-absorbing function, will obviously tend to rise and be returned from each subsidiary reservoir to the reservoir antecedent thereto through the uppermost of the conduit means shown, for re-cooling.

When the heat transfer and exchange fluid is of optimum characteristics, the necessity for substantial difference in levels between each reservoir and its antecedent reservoir is considerably reduced, yet some difierence in the elevation between the several subsidiary systems should preferably be provided where thermosiphonic action alone is relied upon for flow of the heat transfer and exchange fluid.

There are, however, some conditions which make desirable the installation of the master secondary reservoir l5 and the auxiliary cold source heat-dissipating tank 4| below the levels of the ultimate heat transfer and exchange units. This problem may be solved, among other similar methods, by the arrangement which is described immediately hereinbelow.

Referring now to Fig. 4, the general arrangement of the over-all structure and the conduits leading to and from the subsidiary secondary reservoirs I6, 26 and 33 and the ultimate heat transfer and exchange units 23, 3| and 39 will be seen to be generally the same as have been previously described. That is to say that as far as possible, the units comprising the subsidiary system and the branch system or systems subsidiar thereto are arranged at respective elevations sufficient to permit thermo-siphonic flow of the heat transfer and exchange fluid.

However, with the master secondary reservoir 15 at the low level shown for it, it is obviously impossible to get flow of heat transfer and exchange fluid from such reservoir to the subsidiary secondary tanks or reservoirs by thermo-siphonic action alone, and therefore the fluid must be cit! culated by pump means. To achieve this object, in this modification, a pump 45 is utilized, such pump being mounted in the line of a main conduit comprising conduit portions 41, 41'. Pump 45 is driven by an electric motor 46 or other driving means.

As shown at the upper right hand side of Fig. 4, the conduit 24 from ultimate heat transfer and exchange unit 23 in this instance has in its length a temperature control means 48, typically in the form of a thermostatic valve, which precludes the flow of heat transfer and exchange fluid between such unit and subsidiary secondary reservoir l6 except at periods when the temperature differential between such structures is in undesirable imbalance. When the temperature rises above desired levels in conduit 24 the thermostatic valve 48 opens and in so doing closes a switch 49 suitably connected into an electric circuit 50 which controls operation of pump-driving motor 46. Simultaneously, electrically actuated valve which is also in circuit 50 and energized by closure of such circuit, is opened. The operation of the pump 45 thereupon circulates the heat transfer and exchange fluid from master secondary reservoir |5 through heat exchanger thereby lowering the temperature of the heat transfer and exchange fluid in subsidiary secondary tank or reservoir l6. Heat transfer and exchange fluid will then flow thermo-siphonically from reservoir l6 through heat exchanger 22 (Fig. 2) in ultimate heat transfer and exchange unit 23 until the desired temperature is reached in such unit, whereupon thermostatic valve 48 will close, in so doing breaking the motor operating circuit maintained by switch 49, thus inactivating the motor and pump and also causing electrically actuated valve 5| to close. A check valve 52 may be inserted in the main conduit portion 41' to assure that pump 45 will at all times be fully primed.

The combined pumped and thermo-siphonic flow of the heat transfer and exchange fluid is regulated for subsidiary secondary reservoir 26 and its associated subsidiary branch or ultimate heat transfer and exchange unit 3| by the coacting series of elements comprising thermostatic valve 53, switch 54 and electrically actuated valve 55; and for subsidiary secondary reservoir 33 and its associated subsidiary branch or ultimate heat transfer and exchange unit 39 by the coacting series of elements comprising thermostatic valve 55, switch 51 and electrically actuated valve 58, all of which function independently or in unison, as described above, with respect to those similar elements associated with subsidiary secondary reservoir l6 and its branch which terminates in ultimate heat transfer and exchange unit 23.

With the auxiliary system tank 4| located at a level lower than the reservoir l5, positioned, for example, in a spring or well, it is also necessary to pump-circulate the heat transfer and exchange fluid in the auxiliary system of which such tank is part. To do this, a conduit 42 is provided which communicates between main con- 'duit 41 and the bottom of tank 4|, the flow through the conduit being controlled by a temperature control means 43 typically comprising a thermostatic valve. Another conduit 44 communicates between the upper portion of tank 4| and reservoir l5 adjacent the top of the latter. It will be clear that during operation of pump 45 heat transfer and exchange fluid will be circulated through tank 4|, thereby dissipating heat units through the latter.

It will be obvious that there is provided by the apparatus described immediately hereinabove structure whereby the thermo-siphonic flow of heat transfer and exchange fluid may be maintained within certain portions of the secondary system due to their relative positioning and that the flow of such fluid to certain other portions of the secondary system may be augmented by pump means. It will be further obvious that any single subsidiary secondary reservoir or any system comprising any combination of such reservoirs and associated still further subsidiary system may function under pump-induced flow generally in the same manner as described above.

Now referring to Fig. 5, there is therein shown another optional form of the invention wherein the subsidiary secondary reservoirs are eliminated and the heat transfer and exchange fluid from the master secondary tank or reservoir I5 is circulated directly to the ultimate heat transfer and exchange units such as the coils or hollow wall portions of the refrigerating compartments illustrated in Fig. 2. The modified structure shown as comprising this system achieves a few of the accomplishments of the over-all system wherein subsidiary secondary reservoirs are interposed between the master secondary reservoir and the ultimate heat transfer and exchange units, but in some instances and applications this form is adequate. In installations of this kind it has been found best to provide sufiicient heat transfer and exchange fluid capacity in master secondary reservoir l5 so that it will contain about twice the amount of heat transfer and exchange fluid as the heat transfer and exchange systems subsidiary thereto.

It will be noted that in this instance there is provided at one side of the master secondary reservoir |5 a header 2|5 above the level of the base of the primary thermal conditioning means to serve the same function as header I I5 shown in Fig. 1 and that the evaporator H3 is directly immersed in the heat transfer and exchange fluid in master reservoir l5.

Now referrin to' Fig. 6, there is therein shown still another form of the invention. In this modification the primary thermal conditioning means is mounted on a hollow channelled base 3' formed within which is the evaporator. This base is securely clamped in planar heat exchange relationship with master secondary reservoir l5. In this instance reservoir I5 is provided with a top of heat conductive metal which readily permits heat exchange by conduction between the heat transfer and exchange fluid in master reservoir l5 and the evaporator, As in the case of the showing of Fig. 1, a header 2| 5 is provided to permit expansion and contraction of the heat transfer and exchange fluid and to assure continuous contact of such fluid with the top of the reservoir 5. It will be appreciated that the hollow base |3' can be arranged to contact any desired portion of the surface area of reservoir I5.

Up to this point the structures and independent but correlated heat transfer and exchange systems comprising the invention have been shown and described as being applied wholly to refrigeration. For refrigeration purposes, where thermo-siphonic flow of the heat transfer and exchange fluid is entirely relied upon for circulation of such fluid, it is obvious that the entire secondary system including its subsidiary and branch reservoirs or tanks should be positioned below the tank in which the evaporator of the primary thermal conditioning means is located where, as in Fig. 1, such a tank is rovided, or, at any rate below the cold producing evaporator and the master secondary reservoir, however these elements may be correlated. It is also obvious that to induce thermo-siphonic flow between the master secondary reservoir, the subsidiary secondary reservoirs and those other reservoirs or similar elements which form the more remote or the ultimate heat transfer and exchange means or units (for example, the compartments 23, 3!, or 38 and associated structure of Fig. 1) these intermediate and ultimate heat transfer and exchange structures should be positioned in stepped fashion below that reservoir to which each is subsidiary.

It is also obvious that where the respective reservoirs cannot be positioned in the respectively steppe positions most desirable for fully thermo-siphonic flow of the heat transfer and exchange medium, pump flow can readily be wholly or partially substituted for thermo-siphonic flow between any desired portions of the system.

Further, up to this point only the evaporator side of the thermal conditioning means has been shown and described as being productively utilized, the heat from the condenser being dissipated.

Thus, were the system reversed, i. e. with the condenser positioned in heat transfer and exchange relation to a volume of heat transfer and exchange fluid in a master heat secondary reservoir, and were its immediately subsidiary reservoirs and those subsidiary to the latter positioned to be at correspondingly higher positions with respect to one another, structures and methods similar to those hereinbefore described would as Well function for heating purposes as for refrigeration use. Obviously, pump induced flow as well as thermo-siphonic flow of the heat transfer and exchange fluid can be used in any portion of the system, generally in the same manner as has been described with respect to the refrigeration use of the structures and methods of the invention.

The same thermal flywheel effect, and other corresponding advantages including control, regulation, transfer and exchange of heat units can be had in a heating system as are had in a refrigerating system and, of highest importance, dual use may be had of the heat unit collecting and dissipating characteristics of a conventional thermal conditioning means having both an evaporator and a condenser.

Typical of dual use of refrigeration and heating, in a restaurant, the ice cream, meats, milk products and similar perishables require refrigeration and the steam tables, roll warmers, coffee makers and other like units require heat. In present restaurant practice primary thermal conditioning means utilized for refrigeration results in a nearly total loss of readily usable heat, while coal, gas, and electricity are consumed to produce heat for other fixtures requiring it, and these fixtures, having opposite uses, are often in close juxtaposition. Thus, by the use of apparatus similar to that about to be described, the heat from cooking devices and from the restaurant itself as well as the heat extracted .by use of refrigerating apparatus may be re-captured and reused not only for heating the necessary units but also for heating the restaurant itself in cold weather.

Referring now to Fig. 7, the over-all refrigeration system including the refrigeration master secondary reservoir, the subsidiary secondary systems and still further subsidiary systems shown at the lower right hand side of the drawing are very much like the showings of similar structure in Figs. 1 and 2.

In Fig. 7, reference numeral 3"] indicates a primary thermal conditioning means which in this instance comprises a motor, compressor, condenser, receiver (not shown), expansion valve and evaporator, and having a temperature control means 3| l. Primary thermal conditionin means 31 D is shown as being mounted medially of a tank structure generally indicated 3l2 having at its one side a refrigeration master secondary reservoir 3|3 and at its other side a heat master secondary reservoir 3l4. Extending downwardly into master secondary reservoirs 3I3, 3 l4 are primary tanks 3l5 and 316.

Primary tanks 3i5 and 316 and master secondary reservoirs M3 and 3l4 all contain a suitable heat transfer and exchange fluid. The primary thermal conditioning means evaporator 311 is immersed in the fluid in tank 3l5 and its condenser 3I8 is immersed in the fluid in tank 3l6. An expansion valve 3l9 is interposed in the conduit 320 which interconnects the evaporator and the condenser.

The entire unit comprising the primary thermal conditioning means, including its condenser and evaporator, is unitarily removable from the main tanks in which the evaporator and condenser are positioned, without disturbing the secondary systems, by removing the normally bolted down covers 32l and 322.

Master secondary reservoirs 3 I 3, 314 may, if desired, be provided with header spaces 323 and 324 to permit expansion and contraction of the fluids in such reservoirs. It will be obvious that the fluids in each primary tank and the master secondary reservoir with which each tank is associated are in such heat exchange relation that their respective temperatures are normally maintainable within a limited common temperature range.

Since the tank structure 3l2 comprises refrigeration and heat master secondary reservoirs 313, 3 M, respectively, an insulating partition 325 is interposed between such reservoirs to prevent heat exchange therebetween. Leading outwardly from the refrigeration master secondary reservoir 3|3 is a master conduit 330 which forms a common heat transfer and exchange fluid supply means for certain of the hereinafter described subsidiary secondary reservoirs which form a part of the subsidiary secondary system. Branched from master conduit 330 are other conduits 331, 332 and 333 leading into communication or association with the below-described subsidiary secondary reservoirs, as shown.

Conduit 33l communicates with a heat exchanger 334 which is contained within subsidiary secondary reservoir 335, a conduit 336 leading from the top of such heat exchanger and communicating with reservoir 3l3 adjacent its top. Reservoir 335 also contains a suitable heat transfer and exchange fluid. A temperature control means 331 comprising, typically, a thermostatic valve, is shown as interposed in the line of conduit 336 to regulate the flow of heat transfer and exchange fluid therethrough, limiting the flow of such fluid between heat exchanger 334 and reservoir 313 to times when the heat transfer and exchange fluid in reservoir 335 rises to a temperature undesirable therefor.

.345, being positioned on the latter.

13 tom of the latter, and a conduit 34! communicates between the top of such reservoir and the top of master secondary reservoir 3l3. A temperature control means 342, typically in the form of a thermostatic valve, limits the flow of heat transfer and exchange fluid between subsidiary secondary reservoir 340 and master reservoir 3|3 to periods of time when the respective volumes of such fluids are in undesirable thermal imbalance.

Conduit 333 communicates between main conduit 330 and one side of a removable heat exchanger 35l, later hereinafter described, which is associated in heat transfer and exchange relation with the fluid in subsidiary secondary reservoir A conduit 346 communicates between the heat. exchanger and master secondary reservoir 313 at a point adjacent the top of the latter. A temperature control means 341, typically in the form of a thermostatic valve, is interposed in the line of conduit 346 to limit the flow of heat transfer and exchange fluid between heat exchanger 35l and heat exchanger thereby making of the reservoir 345 a master secondary reservoir. Obviously where similar structure is provided any subsidiary secondary reservoir, wherever located in the systems, may be converted to a master secondary reservoir or changed to be served by another unit antecedent thereto, or changed from one system to another, thereby permitting expansion or contraction of a system, after installation, as conditions may require.

Each above-mentioned subsidiary secondary I reservoir is preferably provided with a header, reference numerals 348, 349 and 350 indicating. respectively, the headers on reservoirs 335, 34c and 345. As has been previously mentioned, these headers substantially accelerate thermo-siphonic flow of the heat transfer and exchange fluid.

The ultimate heat transfer and exchange unit served by subidiary secondary reservoir 335 comprises a heat exchanger 355 shown in the form of a coil positioned within the walls of a compartment 356, which might typically be a movable member such as a refrigerated drawer in a bottle cooler or the like. A heat transfer and exchange fluid conduit 351 communicates between the lower end of heat exchanger 355 and the lower portion of subsidiary secondary reservoir 335 and another conduit 358 communicates between the upper end of such heat exchanger and the upper portion of such reservoir. A temperature control means 359, usually in the form of a thermostatic valve, is interposed in the line of conduit 358 to permit or preclude flow or heat transfer and exchange fluid between the ultimate heat transfer and exchange unit 355 and subsidiary secondary reservoir 335 when the fluid in such unit is at an undesirable or a desirable temperature, respectively. A

To permit compartment 356 to move or swin conduits 351, 358 are provided with flexible tube portions 351a and 358a, respectively, as shown.

The ultimate heat transfer and exchange unit served by subsidiary secondary reservoir 340 comprises a hollow wall portion 360 of a compartment 36I which, in a restaurant installation, might typically be a swinging-shelf-type frozen food compartment.

A heat transfer and exchange fluid conduit 362 communicates between the lower part of hollow wall portion 360 and the lower part of subsidiary secondary reservoir 340, and another conduit 363 communicates between the top of the hollow wall portion and a position in reservoir 340 elevated above that point with which conduit 360 communicates with the latter. A temperature control means 364 permits or precludes flow of heat transfer and exchange fluid within selected ranges between the above-named subsidiary secondary reservoir and the hollow wall portion 350 and its associated compartment 361.

To permit compartment 361 to be moved or swung with respect to reservoir 34!! which serves it, conduits 362, 363 have in their length flexible tube portions indicated, respectively, by reference numerals 362a and 363a.

Referring now to the showing at the extreme bottom right hand portion of Fig. 7, it will be seen that conduits 310, 31I communicate with subsidiary secondary reservoir 345 at, respectively, lower and higher levels of the latter and terminate, respectively, at lower and higher levels in communication with a hollow bottom portion 312 forming an ultimate heat transfer and exchange unit integral with a compartment 313. Compartment 313 in a restaurant application might t pically be a bottle cooler in which the bottoms of the bottles repose in heat-conductive contact with the upper surfaces of hollow bottom portion 312. A temperature control means 314, typically in the form of a thermostatic valve, is interposed in the line of one of the aforementioned conduits, in this case conduit 31!, to shut off the flow'of heat transfer and exchange fluid between portion 312 and subsidiary secondary reservoir 345 when the temperature of the heat transfer and exchange fluid in the hollow bottom portion is in desired temperature relation to that fluid in the subsidiary secondary reservoir 345.

It will be obvious from the foregoing that subsidiary secondary reservoirs 335, 340 and 345 and their associated conduits and controls comprise individual systems, subsidiary to master secondary reservoir 3 IS, in which the heat transfer and exchange fluid in any one or all of the former of which may be maintained, if desired, at a temperature differential to that of the similar or same fluid in the master secondary reservoir; and it will be further obvious that the heat transfer and exchange fluid-containing portions of compartments 356, 36! and 313, together with their several integrated individual conduits and controls together with the compartments or the like with which the fluid-containing portions are associated constitute branch systems served by the subsidiary secondary reservoir systems forming, in this instance, ultimate heat transfer and exchange units, the temperatures in the heat transfer and exchange fluid contained in which may be maintained at a differential to the same or similar fluid in the subsidiary secondary system by which each branch is served.

Still referring to the lower right hand portion of Fig. 7, shown diagrammatically below master secondary reservoir M3 is a tank 380 having a header portion 38]. Tank 38B is exposed to natural conditions, as, for instance, those occurring in a spring or well, to function as a heatdissipating or cold accumulating means to supplement the function of the cold producing means otherwise shown.

Tank 380 and its below-described associated conduit system contains a quantity of heat transfer and exchange fluid and is preferably provided with fins 382. A heat transfer and exchange fluid conduit 383 communicates between the bottom of tank 380 and the bottom of a heat exchanger 384, shown in this instance as being of the coil type, and another conduit 385 communicates between the upper levels of the heat exchanger and a point adjacent the top of the tank. Heat exchanger 384 in this instance is shown as being positioned in subsidiary secondary reservoir 335 and in heat transfer and exchange relation to the fluid in the latter. A temperature control means 386, usually in the form of a thermostatic valve, is interposed in the line of one of the conduits communicating between tank 380 and subsidiary secondary reservoir 335, in this instance shown as being in the line of conduit 385, this valve being so set as to preclude flow of heat transfer and exchange fluid within the closed system comprising tank 380, conduits 383, 385 and heat exchanger 384 during periods of time when the fluid in tank 380 is warmer than the similar fluid in reservoir 335.

Referring now to the upper left hand portion of Fig. 7, wherein are shown typical systems and arrangements for utilizing the inventive concepts herein disclosed in heating apparatus, it will be seen that a heat exchanger 400 is immersed in the heat transfer and exchange fluid in master heat secondary reservoir 314. Heat exchanger 400 is shown diagrammatically as being of the coil type but obviously may be of any other form as, for instance, the plate type.

The upper portion of heat exchanger 400 communicates with a master conduit 40! in the line of which is a motor driven pump 402, the motor of which is not shown. Master conduit 40! communicates by means of a conduit 403 with the upper portion of a subsidiary secondary reservoir 405 and a conduit 404 communicates between the bottom portion of subsidiary secondary reservoir 405 and another heat transfer and exchange fluid master conduit 406. Master conduit 406 communicates with the lower portion of heat exchanger 400, as shown.

Typically, another type of subsidiary secondary reservoir 4I0 may be in communication by means of a heat transfer and exchange fluid conduit 40'. with master conduit 40l adjacent the top of the former, and another conduit 408 communicates between lower portions of such reservoir and master conduit 406. A temperature control means 409, generally in the form of a thermostatic valve, is shown as being in the line of conduit 40! to shut off flow of fluid from master conduit 40| into reservoir 4H1 when the temperature of that volume of the same fluid in subsidiary secondary reservoir 410 is at the temperature desired.

Reference numeral 4| 5 indicates a type of subsidiary secondary reservoir which contains a wholly enclosed volume of heat transfer and exchange fluid. This enclosed volume of fluid is brought to desired temperature by means of a heat exchange 4l2 having a conduit 4| l communicating between its upper portion and master conduit 40! and having another conduit 413 communicating between its lower portion and fluid master conduit 406. A temperature control means 4", for instance, a thermostatic valve, is

shown as being interposed in the line of conduit 4 to limit flow of heat transfer and exchange fluid through heat exchanger M2 to times when the temperature of the inert fluid in reservoir 4| 5 is lower than required.

Still another :form of subsidiary secondary reservoir having great utility in the heat-use application of the invention is shown below the above-described reservoir 5, In this instance, the subsidiary secondary reservoir is indicated by reference numeral 420 and contains an enclosed volume of heat transfer and exchange fluid. The enclosed fluid is heated by a heat exchanger in the form of an enlargement 42I of master conduit 40!, the enlargement having thereon heat-dissipating fins 422.

Referring again to pump 402, this unit should be of a type which freely permits passage therethrough of the fluid in master conduit 40| by thermo-siphonic action when the pump is not being driven; and under driven conditions it should flow the heat transfer and exchange fluid with desired rapidity at all times through master conduit 40!, its enlargement 42!, the subsidiary secondary reservoir 405, master conduit 406 and heat exchanger 400; and under open conditions of temperature control means 409 and 414 it will also flow the conduit-borne fluid through subsidiary secondary reservoir M0 and through heat exchanger 2.

To accommodate expansion of the heat transfor and exchange fluid passing therethrough, both subsidiary secondary reservoirs 405 and M0 are provided with expansion heads 423, 424, respectively.

It will be obvious that reservoirs 405, M0, M5 and 420 comprise subsidiary systems in which, as in the case of reservoir 405, the heat transfer and exchange fluid contained in the associated conduit system master conduits MM, 406, may have free, unrestricted thermo-siphonic and/or pump-induced flow therethrough; in the case of reservoir M0 the flow of fluid is open to the interior of such reservoir but restricted by temperature control means to periods wherein the temperature of the separate volume of the same fluid in the reservoir is at an undesirable thermal imbalance to that portion of the secondary system antecedent thereto; in the case of reservoir 4| 5 the flow of fluid between master conduits 40!, 406, respectively, is restricted to the confines of a heat exchanger and is further limited to flow in the heat exchanger, by temperature control means, to periods of time when the non-flowing fluid in the subsidiary secondary reservoir is undesirably 10011181 than the fluid in the master conduit system; and in the case of reservoir 420 the heat exchange relation between master conduit enlargement 42! and the inert fluid in the immediately aforementioned reservoir permits unrestricted flow of the fluid through the conduit while bringing the fluid in the reservoir to a temperature range approximating that of the fluid in the conduit.

Served by the subsidiary secondary reservoirs described hereinabove are branch systems, shown in this instance as ultimate heat transfer and exchange units in the form of heat-dissipating radiators or the like. Since these ultimate units rely predominantly upon heat reception by convection involving thermo-siphonic flow of the heat transfer and exchange fluid therein, these ultimate heat dissipation units are preferably elevated with respect to the sub- 17 sidiary secondary reservoirs by which they are served.

In the case of the ultimate heat transier and exchange unit served by subsidiary secondary reservoir 405 it will be seen that a conduit 501 communicates between the upper levels of reservoir 405 and reservoir 500 and another conduit 502 communicates between the respective lower levels of such reservoirs. Reservoir 500 has on it a header 503. A temperature control means 564, typically a thermostatic valve, is shown as being interposed in the line of conduit 501 to limit flow of fluid between such reservoirs to periods of time when the temperature of the volume of fluid in reservoir 500 is undesirably colder than the volume of the same fluid in reservoir 4'05.

Subsidiary secondary reservoir 410 is in heat transfer and exchange relation with the ultimate heat transfer and exchange unit 505 served thereby by means of the heat exchanger 506 which is immersed i the fluid in subsidiary secondary reservoir 410. A conduit 50! communicates between the upper portion of heat exchanger 505 and the reservoir mentioned at a point adjacent the upper level of the fluid in the reservoir, and another conduit 560 communicates between the lower portion of heat exchanger 506 and the lower part of reservoir 505. A temperature control means 511 may be utilized, being interposed in the line of conduit 501 to permit free flow of heat transfer and exchange fluid in the closed system comprising reservoir 505, conduits 501, 508 and heat exchanger 506 when the temperature of the fluid in such reservoir is undesirably low in relation to that of the fluid in reservoir 410. Reservoir 505 has on it a header 512 to permit expansion of the fluid contained in the former.

The branch system served by closed subsidiary secondary reservoir 415 is identical to that shown and described with respect to the system associated with subsidiary secondary reservoir 410. This branch or further subsidiary system includes reservoir 510, forming an ultimate heat transfer and exchange unit, the conduits 513, 514, forming, respectively, upper and lower intercommunicating means between reservoir 510 and a heat exchanger 525. A temperature control means 516 may be in the line of conduit 513, typically a thermostatic valve, which would shut oif flow of heat transfer and exchange fluid between the heat exchanger and the reservoir operatively intercommunicating therewith, when the temperature of the fluid in the latter reaches a desired temperature. Like the other above-described reservoirs, forming the ultimate heat transfer and exchange units (500 and 505) reservoir 510 has on it a header 51'! to permit expansion of the fluid in the reservoir.

The ultimate heat transfer and exchange unit served by subsidiary secondary reservoir 420 comprises the reservoir 515 having a header 522 thereon, a heat exchanger 520 and conduits 518, 519 connecting, respectively, the upper and lower portions of the heat exchanger with the upper and lower portions of reservoir 515. A temperature control means 521, again usually a thermostatic valve, permits the flow of heat transfer and exchange fluid between the heat exchanger and the reservoir by which it is served when the temperature of the fluid in the terminal reservoir is below a desired level and precludes flow when the fluid is at a desired level.

The over-all heating and refrigerating system shown in Fig. '7 should have means associated 18 with it for balancing the heating and refrigerating load. Obviously, conditions could be encountered wherein an unusual demand on either side might develop on the opposite side an excess of the desirable amount of the converse condition of heat or cold.

Illustratively, suppose an unusual and continuous demand for heat were made upon ultimate heat transfer and exchange units 500, 505, 510 and 515. This would tend to rapidly cool the fluid in these units and the temperature control means 504, 511, 516 and 521 would thereupon permit flow of heat transfer and exchange fluid through the units. This would rapidly withdraw heat units from the volumes of the same fluid or the separate fluids in the subsidiary secondary reservoirs, the temperature control means associated with any subsidiary would open, and pump 402 would be called upon to circulate the fluid through the master conduits and associated units, as well as through the heat exchanger 400. Ultimately the temperature of the fluid in master heat secondary reservoir 314 would be reduced to the point that the primary unit motor and compressor 310 would be brought into operation.

Assuming a normal or less-than-usual demand for refrigeration, the operation of the primary unit might create in the fluid in master cold secondary reservoir 313 an undesirable temperature condition.

As previously mentioned, the converse situation could also happen. An excessive continuous demand for refrigeration might ultimately cause the build-up of an undesirable heated'condition of the fluid in master heat secondary reservoir 314.

It will be obvious that under conditions wherein a large amount of heat were required by the heating side and where the temperature of the heat transfer and exchange fluid in the cold side master secondary reservoir were at an extremely low level, the primary thermal conditioning means evaporator, in the absence of balancing means, would have but few heat units upon which to draw, and, in consequence, would be put into operation under conditions wherein its efficiency would be low.

Conversely, if the heat side were at desired levels and an extreme demand for refrigeration developed, the primary thermal conditioning means condenser would have difliculty in dis-' posing of the heat units accumulated by the evaporator, and, in the absence of balancing means, the primary unit would first be forced into an ineflicient operating phase which, if continued, would cause the motor of the unit to become overheated and perhaps to burn out.

To take care of this situation, should it develop, there is provided the heat dissipating and procuring means described hereinafter.

To dissipate undesirable accumulation of heat units from master heat secondary reservoir 314 conduit means 601, 602 are provided in communication between a heat exchanger 605 positioned in master heat secondary reservoir 314 and a heat dissipator 600. A motor-driven pump 603, the motor of which is not shown, is in the line of one of the conduits and temperature-controlled switch means 604, in the electric circuit into which the motor is connected, puts the motor and pump 603 in operation only at such times as the temperature of the heat transfer and exchange fluid in reservoir 314 is at an undesirably high evel.

To absorb a desired amount of heat to counteract the effect of production-above-usage of refrigeration, a heat absorber 100 is provided. Heat absorber 100 is in communication by means of conduits 10 l, I02, with a heat exchanger I positioned within master cold secondary reservoir 313. A motor-driven pump 103, the motor of which is not shown, is in the line of one of such conduits and temperature controlled switch means 104, in the electric circuit into which the motor is connected, puts the motor and its interengaged pump 103 in operation. The temperature-controlled switch is set to operate only when the temperature of the heat transfer and exchange fluid in reservoir 3 is at an undesirably low level.

Throughout the description to this point, reference has many times been made to the heat transfer and exchange fluid. Several types of fluid, either liquid or gas, or both, may be used individually or in separated combination in the system comprising the invention. The type and kind of heat transfer and exchange fluid is dependent on what is to be expected of it under its particular conditions of use, i. e., the temperature range within which the system containing it is to operate and the characteristics of the fluid as to conductivity, specific heat, density, viscosity, fusion points, etc., within the required temperature ranges. Illustratively, it will be obvious that the heat transfer and exchange fluid in the primary cold and heat tanks I 4 (Fig. 1) or 315, SIB (Fig. 7) serve only for heat unit exchange purposes. Thus, for refrigeration purposes, a fluid having a relatively high fusion or freezing point, water, for instance, would normally not be feasible for use in tank I! and the secondary systems associated therewith because of the tendency of water to freeze. However, on the heating side, if the system were one operating at less than the boiling point of water, the latter might be readily usable throughout the heat system as the heat transfer and exchange fluid. If temperatures above the boiling point of water were developed, a fluid having a higher boiling point than water might be used in tank 3 H5, or in master secondary reservoir 3 I4, and water might be used in the subsidiary secondary system therebeyond; or, as in the case of that form of the structures shown in Fig. 'l' as third from the top at the upper left, wherein reservoir 510 is the ultimate heat transfer and exchange unit and subsidiary secondary reservoir M5 is the portion of the system immediately antecedent to the named ultimate heat transfer and exchange unit, water might well be the heat transfer and exchange fluid in reservoir 5m, and its associated conduits leading to and from heat exchanger 525 and a light oil or a glycerine base fluid might be used as the heat transfer and exchange fluid in subsidiary secondary reservoir 415.

It will thus be apparent that a great variety of heat transfer and exchange fluids may be used. Typical forms of fluids found useful under variant conditions are methyl chloride, water, alcohol, brine solutions, oils, and the like.

It will be obvious that to some degree the structures of the several interrelated but independent heat transfer and exchange systems may be varied in accordance with the type of heat transfer and exchange fluid or fluids used. For instance, whether the subsidiary secondary reservoirs or those heat transfer and exchange units therebeyond are or are not hermetically sealed will depend a good deal on the type of the heat transfer and exchange fluid used.

One heat transfer and exchange fluid which has been found highly satisfactory for use in the secondary and ultimate heat transfer and exchange units, when used for refrigeration purposes, has been used extensively in refrigerated trucks and the like and is sold under the trade name Thermeran The exact chemical composition of this heat transfer and exchange fluid is not known.

When using heat transfer and exchange fluid of the type immediately hereinabove indicated for refrigeration purposes, the several fluid-containing tanks and reservoirs and their associated conduits are completely filled with the fluid, the temperature of such fluid being raised to about 70 F. The reservoirs are then hermetically sealed. This particular heat transfer and exchange fluid contracts when the temperature is reduced below 70 F., thus when the temperature is lowered, as will be done at in-use refrigeration temperature ranges, the fluid contracts and headers H5, H6, I26 and I33 (Fig. 1) Or the similar elements 323, 348, 349 and 350 (Fig. 7) will be under partial vacuum and this vacuous condition accelerates thermo-siphonic flow of the fluid within the system.

In the drawings and description the structures have all been directed to a system including a compressor-condenser-evaporator unit. It will be obvious that the primary unit of the type described is merely a convenient means of supplying heat or, conversely, its condition of absence, cold, and that other primary thermal conditioning means may be substituted therefor.

From a refrigeration standpoint, in larger installations, due to the necessity for high reserve heat unit absorbing capacity in the master secondary reservoir, usually greater refrigerating ability is required in the portions of the entire systems therebeyond than can be had from waterice because of its relatively high melting temperature. However, for certain installations, waterice or water-ice and an accelerator such as salt may be used as the cold source. Solid carbon dioxide is a convenient primary thermal conditioning substance which is now readily available and this product has been found satisfactory for many types of refrigeration applications utilizing the structures of this invention.

When water-ice or Dry Ice is used as a primary thermal conditioning means, tank I4 (or 3l5) may be utilized as 9. dry non-fluid containing tank or receptacle.

From a heating standpoint, the primary thermal conditioning means, in addition to those heatproducing means shown in Fig. 7, typically may be a gas or other type fire or flame, an electrical heating unit, or any other source of heat.

Wherever temperatures are mentioned herein in terms of degrees, they are to be interpreted in terms of the Fahrenheit scale.

Hypothetically illustrative of use of the refrigeration structure shown in Fig. 1, let it be assumed that the temperature control means 9 were set to maintain the heat transfer and exchange fluid in tank l4 within a temperature range of, say, 20 to 30 F. The heat transfer and exchange fluid in master secondary reservoir l5 will be found, under usual conditions, to be maintained approximately within the range indicated hereinabove. In the absence of temperature control means such as that indicated by reference numeral 20, it will be obvious that the temperature of the heat transfer and exchange fluid in subsidiary secondary reservoir I6 would 

